feat: add visual indicator for list output slots (#8766)

## Summary

Add rounded square dot shape and "(Iterative)" tooltip for list-type
output slots in Vue nodes, matching litegraph's visual indicator.

## Changes

- **What**: `SlotConnectionDot.vue` renders `rounded-[1px]` instead of
`rounded-full` when slot shape is `RenderShape.GRID`. `OutputSlot.vue`
appends "(Iterative)" to the tooltip for these slots.

<img width="807" height="542" alt="Screenshot 2026-02-10 at 03 38 42"
src="https://github.com/user-attachments/assets/137b60c5-ac3b-457f-a52d-58f5f28a59ea"
/>


## Review Focus
- i18n key added for the iterative suffix

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8766-feat-add-visual-indicator-for-list-output-slots-3036d73d3650813aad85ce094d29c42b)
by [Unito](https://www.unito.io)

src/locales/en/main.json

@@ -2834,6 +2834,9 @@
       }
     }
   },
+  "vueNodesSlot": {
+    "iterative": "(Iterative)"
+  },
   "vueNodesBanner": {
     "title": "Introducing Nodes 2.0",
     "desc": "– More flexible workflows, powerful new widgets, built for extensibility",